1. Field of Invention
This invention relates to body warmers, specifically to such warmers which are applied externally for joint and muscular pain relief and muscle relaxation.
2. Description of Prior Art
Drugstores commonly supply consumers with body warmers operating on a variety or principles. Originally the choice of body warmers was limited to water bottles and herbal preparations. The latter included infusions, decoctions, fomentations, poultices, salves, extracts and plasters. These preparations contained either active substances extracted from medicinal plants and herbs by hot water or alcohol, or herbal material ground to fine powder in order to enhance and accelerate the desired action of medicinal herbs. Warming plasters widely used in the past consisted of a piece of cloth coated on one surface with a glue mixed with powdered plant material such as red pepper (botanical name Capsicum) pods, or mustard (botanical name Brassica) seed. The warming plasters worked by rubefacient, action of powdered plant material causing reddening of skin and enhanced body heat production when applied directly to skin surface. These plasters could be applied for a limited time only to avoid excessive skin irritation and were unpleasant in use and especially during removal, as body hairs glued to the plaster were pulled out. The heating plasters have been abandoned altogether, and are no longer available on the market.
Thereafter inventors created several types of body heaters, including electric heaters, moist heating pads, microwaveable gel or fluid heaters, chemical heaters, and warmers retaining body heat.
In electric heaters, heat is produced by electric current flowing through a conductor of appropriate resistivity. The conductor is insulated and embedded in a flexible sheath that is:
(a) wrapped around the desired body part and fastened in place, for example U.S. Pat. No. 4,736,088 to Gordon B. Bart (1988) PA0 (b) shaped as a piece of garment to warm a specific body part, for example U.S. Pat. No. 5,050,595 to Pam Krafft (1991) for women's breast warmers, and U.S. Pat. No. 4,628,930 to Steven N. Williams (1986) for a lower body warmer to prevent menstrual cramps. PA0 (c) shaped as a cushion for use in the seated position; U.S. Pat. No. 4,335,725 to Barbara J. Geldmacher (1982). PA0 (d) containing pouches or packs of heat retaining gel (for example U.S. Pat. No. 5,050,595 cited above) or oil, for example U.S. Pat. No. 4,904,846 to Augustin Oscandal (1990). PA0 a) The electric body warmers using house current require wiring that must be plugged to a wall outlet. This reduces the mobility of the user of the warmer. Electric body warmers are unsuitable for overnight use, because wiring may be inadvertently entangled and broken during sleep. If placed under the body, the electric warmer may cause excessive heat, burning and blistering. Warnings to that effect are printed on packaging of electric body warmers currently on the market. Electric warmers combining a battery as a source of electricity and an electrically heated gel pouch do not reduce the mobility of the user but being bulky and heavy are inconvenient to use. PA0 (b) The action of moist heating pads is of limited duration. They are inconvenient to use, as they require handling of pads while hot. Thc heat distribution is uneven in time, gradually decaying, and the warmer requires frequent re-heating for longer applications. PA0 (c) The gel, and fluid heaters suffer from the same inconveniences in use. The heating action is uneven in time, decaying gradually, and the warmer needs re-heating about every hour for longer application. Moreover, the gel heating pads that contain gel in a plastic pouch may be inadvertently ruptured if placed under the body, resulting in a messy and potentially damaging spill of the gel. Warnings against bursting of the gel pouch under body weight are printed on the packaging of gel heating pads currently on the market. PA0 (d) The warmers retaining body heat contain no external heat source and their effectiveness is therefore small. They are additional specialized pieces of clothing designed to retain more body heat than conventional clothing. They are tight and non breathable, and therefore retain perspiration. PA0 (a) to provide a body warmer that can be used for extended period of time without causing skin irritation and pain during removal; PA0 (b) to provide a body warmer that enhances body heat production for greater effectiveness; PA0 (c) to provide a body warmer with prolonged action at constant rate, thus eliminating the necessity of re-heating and handling warm heating pads; PA0 (c) to provide a body warmer that does not reduce the mobility of the user; PA0 (d) to provide a body warmer that can be used both in daytime and overnight. This feature allows the therapeutic use of body warmer during night rest, thus conditioning the body part needing therapy for daytime effort.
Most electric heaters are plugged to house electric current outlets. Some heaters, for example U.S. Pat. No. 5,050,595 cited above, use a portable battery as source of electricity for electric resistivity heating of gel packs that gradually release heat to the body.
Moist heating pads consist of a water absorbent fabric pad and wrap and fasteners to keep the wrap in place. The pad is heated in warm water, or moistened and heated in a microwave oven. The hot pad is then placed against the desired part of the body, wrapped around and fastened in place. The warming effect lasts until the heat stored in the moist pad is dissipated. U.S. Pat. No. 4,207,885 to Richard Hampton and P. Frank Hanes (1980), U.S. Pat. No. 4,753,241 to Patrick J. Brannigan and Gerald L. Peckich (1988), and U.S. Pat. No. 5,135,518 to Barbara Vera (1992) are examples of this type of warmers.
Microwaveable gel, and fluid heaters contain a pouch filled with gel, or fluid of high specific heat capacity, that is heated in a microwave oven and applied to the body. The pouch gradually releases heat for a period of time typically lasting about one hour. The gel pouch is shaped as a pad fastened to the desired part of the body by wrapping a bandage--for example U.S. Pat. No. 4,935,550 to Wayne K. Dunshee (1988), U.S. Pat. No. 4,756,311 to Sam E. Francis Jr. (1988), and U.S. Pat. No. 4,700,706 to Walter Munch (1987).
Other inventors proposed specially shaped pouches containing the heating gel or fluid to fit specific parts of the body. Heaters for feet, for example U.S. Pat. No. 5,050,598 to Dalton J. Tucker (1991), use a bladder fitting inside a slipper or other footwear, or flexible elastic tubing, U.S. Pat. No. 4,214,588 to William H. Byler (1980). Hand mitts for hot or cold therapy--U.S. Pat. No. 5,050,596 to Steven P. Walasek and Stuart J. Walasek (1991) use pockets filled with gel and insulating pockets with dead air space.
Chemical heaters are made in various shapes. They comprise pad or pouches filled with chemical compounds that produce heat. U.S. Pat. Nos. 5,176,134 to Gary C. Hudson (1993); 4,580,547 to Imants P. Kapralis and Harry Krukle (1986); 4,596,250 to Arthur A. Beisang, III, Robert A. Ersek, and Arthur A. Beisang (1986), and 5,046,479 to Akio Usui (1991) are examples of this type of heaters.
The warmers retaining body heat are made of a variety of fabrics consisting of a mix of natural and man-made fibers. Some use a mix of olefin, acrylic, wool and rubber elastane fibers. Other are made of a heat-reflecting metalized fabric facing the body and an artificial fiber fleece back. These warmers come in various shapes as gloves, sleeves and pads. They operate on the principle of retaining body heat and contain no source of heat external to the body. Some comprise a skin contact layer of absorbent fabric impregnated with treatment liquid, for instance U.S. Pat. No. 4,913,957 to David C. Strack and La Donna H. Brown (1990).
All these body warmers suffer from a number of disadvantages: